TESORO GOLDEN SABRE

[ivconic]

No it was not me.
I partially solved audio problem. It is threshold problem actually. So...when better adjusted threshold, audio last longer...simply as that!
Last LM358 has 6.pin connected to minus via 330K resistor and to gnd via 2K2 resistor (33K in some schematics). So remove 330K and put 100K straight to middle pin of 100K trimmer. One end of trimmer goes to +8V and other to minus rail. Adjust with trimmer treshold to level you think is suitable and that is all.... This is taken from some other Tesoro schematic.....
This "mod" changes audio and now sound is a bit better on distant coins or small items.
This is transitive solution for me, until something better appears.
Most likely i will experiment with monostable like Max suggested.
Until than...

[tiktak]

Hi,

Hi,
Thanks.
I had the same feeling.I will try ASAP.
Looks like good simple solution.

[ivconic]

Endless modding continue!

Latest TGSL mod!
Thanks to Max's initial idea i managed to find best solution and already applied on my existing TGSL. Monostabile with 555.
What to say? You must try it to see! This modd is solving all possible TGSL issues at once. Not only that audio lasting is now adjustable, but also stabillity is better. No more feedback relations between speaker and LM358.
I dont want to waste so many words on this. You must try this to see. You will be thrilled!

Time constant is defined with 0.47 and 1M trimmer (or pot).
The rest is history.....

P.S.
Audio is LOUD now! And adjusted to 0.6sec (with showed components) is looooooong! So loooooong! But also could be adjusted on
desired time. As suits your needs. That's why is also good idea to use potentiometer on front panel for that...

[amtech2005]

TESORO GOLDEN SABRE

IVCONIC , Great idea adding "555" delay , it will also save on total current drawn at once and yes be considered more stable when you hit a target . But depending how much you set your delay , will the Pin-Pointing a Target be more difficult ??? Let us know how your prototype works and if you updated the PCB layout file yet...........Eugene

[ivconic]

You have good point. But that's why is neccessary to adjust time not so long and not so short (like it was before). I experimented with it a lot and could not resist to put potentiometer on front panel, instead trimmer inside.
Than is easy to adjust it during working. On "clean" soil, without much of a finds, trash and mineralisation, audio should be a bit longer, so prospector can wipe faster and wider with coil. No danger to miss even smallest metalic items like very small coins 5-6mm diamm. Once item detected, audio can be adjusted to last less and than pinpointing is easy.
I am planing new pcb, but it will not be so soon. I suggest small "piggy" pcb as an upgrade over existing one. Not much work arround it.
Regards!

P.S.
Max gave me idea mentioning monostabile as possiblle solution.
Later working on this mod, other benefits from it appeared also! I had luck more than expected!

[Max]

Hi,
well done !

I like it... wanna try the mod on my TGSL!

Kind regards,
Max

[ivconic]

Max please do that and inform me about. I want to see what are you thinking of it. At me it worked from a start excellent. Also huge difference now, much better behavior. I am very satisfied.

[Max]

Max please do that and inform me about. I want to see what are you thinking of it. At me it worked from a start excellent. Also huge difference now, much better behavior. I am very satisfied.

Hi,
yes... I'll do but after discover the source of troubles at RelicHawk... now I cannot mod the TGSL, I'm doing already other 2 stuff... not MDs.

I think that schematics is really what needed there... just have to find time to check on real circuit... then report.

Kind regards,
Max

[ivconic]

Here is small "piggy" pcb for applying latest mod on already made devices.
What you need is to desolder end of 27K which goes to (B)ase of MPSA13 and connect with wire to "G" point on small pcb. "Out" from small pcb connect with (B)ase of MPSA13. Than connect "+" and "-" to +8V and "gnd" on main pcb and that is all!
Switch it ON and enjoy!

[ivconic]

Pay attention on fet orientation. I draw it with orientation for J107, which is completelly reversed than BF245. So put BF245 reversed...

[eclipse]

OK guys looks like you've done quite a lot team work here to make this wonderfull (simple&nice) schematic. I got just one question:
since i got coil housing for 2D (27sm dia), what are the coil windings and wire type for this search coil? The topic is quite big, if you can save me time reading it, if it is already discussed would be most appriciated.

[nakky]

Use search,save others time writing and writing again .Nakky.

[eclipse]

nakky i don't remember putting a gun to anyone's head saying:
"gimme yar coil data or i shoot", if anyone is pleased to help me - great!
I found coil data for concentric, but not for 2D -27sm.
BTW you are loosing your time too, writing this reply
no offence i really need some help on the coil

edit:
Tesoro coils : think you could use an early lobo design (dd type) params are:
(data from an old kt315 post)

rx 1.35mH 12ohm
tx 10mH 55ohm

Any ideas number of windings/wire diameter?

[Max]

nakky i don't remember putting a gun to anyone's head saying:
"gimme yar coil data or i shoot", if anyone is pleased to help me - great!
I found coil data for concentric, but not for 2D -27sm.
BTW you are loosing your time too, writing this reply
no offence i really need some help on the coil

edit:
Tesoro coils : think you could use an early lobo design (dd type) params are:
(data from an old kt315 post)

rx 1.35mH 12ohm
tx 10mH 55ohm

Any ideas number of windings/wire diameter?

Hi,
recipe of coil is different from other tesoro's... here just uMax detectors could use it, like TGS:

wire is enamelled 30AWG (0.25mm bare copper, 0.27-0.28 with varnish)

DD27cm diameter
100 turns for TX
105 turns for RX
resistance is for both around 20ohm

I've posted some pictures about coil making... find them for more details.

Kind regards,
Max

[eclipse]

Thanks Max. On later stage (when pcb is done, coils are wind) i will probably need some
help to adjust with the scope, thank god i have o-scope...
First i will remake the board, i like the things ultra crowded and so it will fit in the box i have.
I will post pictures when the work in progress has something visual to show